Question

in a test of the effectiveness of garlic for lowering cholesterol, 50 subjects were treated with garlic in a process tablet form. cholesterol levels were measured before and after the treatment. the changes( before - after) in their levels of LDL cholesterol (in mg/dL) have a mean of 5.6 and a standard deviation of 18.1. Construct a 95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. what does the confidence interval suggest about the effectiveness of garlic in reducing LDL cholesterol?

Answer 1

n1 = n2 = n = 50

d-bar = 5.6

s of d-bar = 18.1

% = 95

Degrees of freedom = n - 1 = 49

SE = s/√n = 2.559726548

t- score = 2.009575199

Margin of error = t * SE = 5.143962988

Lower limit of the confidence interval = d-bar - width = 0.456037012

Upper limit of the confidence interval = d-bar + width = 10.74396299

The confidence interval is [0.456, 10.744]

The above interval is entirely positive. This means garlic is effective in reducing LDL cholesterol.

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